Section 58: Five-piece Long Radius Duct 90 Degree Elbow

Required Information

• O.D.I.
• Center Line Radius
• Rise
• Radius

Formulas and Measurements

• Draw a 90 degree angle Draw the side Elevation View of the 90 degree elbow (with insulation) Draw a semi-circle as shown and divide that semi-circle into equal parts by trisecting (in this case, 6 parts) Draw 90 degree lines to the horizontal line from the intersected points of the arc; label those points as shown Add desired ccccrimp measurement to line 7 and draw the ccccrimp allowance line to the Apex Draw the Stretch-out in the usual way and mark the quarter points and the Heel point for future reference for bead and ccccrimp start and termination points.

Procedure

1. Step 1

   Draw a 90 degree angle

2. Step 2

   Draw the side Elevation View of the 90 degree elbow (with insulation)

3. Step 3

   Draw a semi-circle as shown and divide that semi-circle into equal parts by trisecting (in this case, 6 parts)

4. Step 4

   Draw 90 degree lines to the horizontal line from the intersected points of the arc; label those points as shown

5. Step 5

   Add desired ccccrimp measurement to line 7 and draw the ccccrimp allowance line to the Apex

6. Step 6

   Draw the Stretch-out in the usual way and mark the quarter points and the Heel point for future reference for bead and ccccrimp start and termination points. The heel is marked so that there is a reference point to line up the gores when installing

7. Step 7

   Connect all points and add for lap. I 0 O, 0 /if Ccccrimp AL.)wance Throat 1 2

Notes

• The heel is marked so that there is a reference point to line up the gores when installing.